UC2844B Просмотр технического описания (PDF) - Motorola => Freescale

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UC2844B

High Performance Current Mode Controllers

Motorola => Freescale 

UC3844B, 45B UC2844B, 45B

ELECTRICAL CHARACTERISTICS (VCC = 15 V [Note 2], RT = 10 k, CT = 3.3 nF. For typical values TA = 25°C, for min/max values TA is

the operating ambient temperature range that applies [Note 3], unless otherwise noted.)

UC284XB

UC384XB, XBV

Characteristic

Symbol

Min Typ Max Min Typ Max Unit

ERROR AMPLIFIER SECTION

Voltage Feedback Input (VO = 2.5 V)

Input Bias Current (VFB = 5.0 V)

Open Loop Voltage Gain (VO = 2.0 V to 4.0 V)

Unity Gain Bandwidth (TJ = 25°C)

Power Supply Rejection Ratio (VCC = 12 V to 25 V)

Output Current

Sink (VO = 1.1 V, VFB = 2.7 V)

Source (VO = 5.0 V, VFB = 2.3 V)

Output Voltage Swing

High State (RL = 15 k to ground, VFB = 2.3 V)

Low State (RL = 15 k to Vref, VFB = 2.7 V)

(UC284XB, UC384XB)

(UC384XBV)

VFB

IIB

AVOL

BW

PSRR

ISink

ISource

VOH

VOL

2.45 2.5 2.55 2.42 2.5 2.58

V

– – 0.1 –1.0

–

– 0.1 – 2.0 µA

65

90

–

65

90

–

dB

0.7 1.0

–

0.7 1.0

–

MHz

60

70

–

60

70

–

dB

mA

2.0

12

–

2.0

12

–

– 0.5 –1.0

–

– 0.5 –1.0

–

V

5.0 6.2

–

5.0 6.2

–

–

0.8 1.1

–

0.8 1.1

–

–

–

–

0.8 1.2

CURRENT SENSE SECTION

Current Sense Input Voltage Gain (Notes 4 & 5)

(UC284XB, UC384XB)

(UC384XBV)

AV

V/V

2.85 3.0 3.15 2.85 3.0 3.15

–

–

–

2.85 3.0 3.25

Maximum Current Sense Input Threshold (Note 4)

(UC284XB, UC384XB)

(UC384XBV)

Vth

V

0.9 1.0 1.1 0.9 1.0 1.1

–

–

–

0.85 1.0 1.1

Power Supply Rejection Ratio

(VCC = 12 V to 25 V) (Note 4)

Input Bias Current

Propagation Delay (Current Sense Input to Output)

OUTPUT SECTION

Output Voltage

Low State (ISink = 20 mA)

(ISink = 200 mA, UC284XB, UC384XB)

(ISink = 200 mA, UC384XBV)

High State (ISource = 20 mA, UC284XB, UC384XB)

(ISource = 20 mA, UC384XBV)

(ISource = 200 mA)

Output Voltage with UVLO Activated

VCC = 6.0 V, ISink = 1.0 mA

Output Voltage Rise Time (CL = 1.0 nF, TJ = 25°C)

Output Voltage Fall Time (CL = 1.0 nF, TJ = 25°C)

UNDERVOLTAGE LOCKOUT SECTION

Startup Threshold

UCX844B, BV

UCX845B, BV

PSRR

–

70

–

IIB

– – 2.0 –10

tPLH(In/Out)

–

150 300

–

70

–

dB

–

– 2.0 –10

µA

–

150 300

ns

VOL

VOH

V

–

0.1 0.4

–

0.1 0.4

–

1.6 2.2

–

1.6 2.2

–

–

–

–

1.6 2.3

13 13.5

–

13

13.5

–

–

–

–

12.9

–

–

12 13.4

–

12

13.4

–

VOL(UVLO)

–

0.1 1.1

–

0.1 1.1

V

tr

–

50 150

–

50

150

ns

tf

–

50 150

–

50

150

ns

Vth

V

15

16

17 14.5 16 17.5

7.8 8.4 9.0 7.8 8.4 9.0

Minimum Operating Voltage After Turn–On

UCX844B, BV

UCX845B, BV

VCC(min)

V

9.0

10

11

8.5

10 11.5

7.0 7.6 8.2 7.0 7.6 8.2

NOTES: 2. Adjust VCC above the Startup threshold before setting to 15 V.

3. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.

Tlow = 0°C for UC3844B, UC3845B

Thigh = + 70°C for UC3844B, UC3845B

Tlow = – 25°C for UC2844B, UC2845B T high = + 85°C for UC2844B, UC2845B

Tlow = – 40°C for UC3844BV, UC3845BV Th igh = +105°C for UC3844BV, UC3845BV

4. This parameter is measured at the latch trip point with VFB = 0 V.

DV OutputńCompensation

5. Comparator gain is defined as: AV = DV Current Sense Input

MOTOROLA ANALOG IC DEVICE DATA

3

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